Heat exchanger for a steam raiser with support



May 5, 1970 M. WEBER 3,509,939

HEAT EXCHANGER FOR A STEAMRAISER WITH SUPPORT I Filed Nov. '7, 196 2, Sheets-Sheet l E 0o 00 0 0 00 0 0 o o o 9 2 o oo oo o oo o O O O0 O0 O0 80 80 80 8008 L /5 bFpQ OO OO OO E QOQOOOOOOO 1 OOOOOOOOOO Inventor- MAX WEBER May 5, 1970 M. WEBER 3,509,939

HEAT EXCHANGER FOR A STEAM RAISER WITH SUPPORT Filed Nov. 7, 196'? 2 Sheets-Shet a I NVEN TOR.

MAX- WEBER United States Patent Office 3,509,939 Patented May 5, 1970 U.S. Cl. 165-162 9 Claims ABSTRACT OF THE DISCLOSURE The heat exchanger is constructed with helically coiled tubular members of slightly conical shape disposed between a displacement member and a casing. A plurality of comb-like carrying rods support the tubes of the tubusecured to the displacement member. The prongs of the carrying rods are bent about the coiled tubes of each tubular member.

This invention relates to a heat exchanger for a steam raiser. More particularly, this invention relates to a heat exchanger for a pressure fired steam raiser or a steam raiser of a nuclear reactor.

Heretofore, heat exchangers for steam raisers have been constructed from a number of tubular members of different diameters which have been composed of helically coiled tubes of equal length and disposed within an annular space defined by a displacement member and a surrounding casing. In several instances, the tubes have been coiled about the displacement member, as in the winding of coils of wire. In such instances, spacing members have frequently been inserted between the layers of tubes to maintain a radial distance between the layers. However, this technique has required the use of a large coiling machine to coil the tubes. Also, with this technique, the inner layers of the tubes cannot be extended without destroying the adjacent layers. In other instances, the tubes have been bent helically to produce cylindrical tubular members of different diameters which have then been axially inserted into one another. However, this latter technique has the disadvantage that a considerable radial clearance must be left between the cylindrical tubular members of diiferent diameters so that the tubular members can be satisfactorily assembled. Also, after assembling, spacing members must be inserted between the tubular members to make the radial distance between the tubular members over the periphery uniform.

Accordingly, it is an object of the invention to obviate the need for spacing members between helically coiled tubular members of a heat exchanger.

It is another object of the invention to reduce the spacing between adjacent tubular members of a heat exchanger to a minimum.

Briefly, the heat exchanger of the invention is constructed of a plurality of tubular members of different diameters which are formed with a slightly conical shape. The tubular members are formed from helically coiled tubes of equal length and are positioned one within the other within an annular space defined by a displacement member and a surrounding casing. Both the displacement member and casing are also formed with a slightly conical shape so as to contain the tubular members.

The conicity of the tubular members (i.e. the differ ence in diameter of a tubular member with respect to its length) is approximately 0.3 to so that the individ ual tubular members can be very simply inserted into one another starting from either the inside or outside.

In one embodiment of the invention, the displacement member and easing which enclose the tubular members are also formed with a slightly conical shape corresponding to the tubular members. In still another embodiment, the tubes of successive tubular members of ditferent diameters are coiled alternately to the right and left so that the twisting forces of the tube members cancel one another.

These and other object and advantages of the invention will become more apparent from the following detailed description and appended claims taken in conjunction with the accompanying drawing in which:

FIG. 1 illustrates a central section through a heat exchanger of the invention with an alternate securing of the carrying rods; and

FIG. 2 illustrates a heat exchanger detail of alternately oppositely coiled tubes.

Referring to FIG. 1, the heat exchanger includes an inner slightly conical hollow displacement member 1 which is open at the bottom and an outer casing or jacket 2 of corresponding conicity to the displacement member 1 surrounding the displacement member 1 in spaced relation to define an annular space. In addition, the heat exchanger includes a packet 3 of tubes built up from helically coiled tubes disposed within the annular space between the displacement member 1 and easing 2.

The packet 3 of tubes is formed by 17 slightly conical tubular members of different diameters which extend continuously over the height of the packet 3. The innermost tubular member 311 comprises three helically coiled parallel tubes which begin at points (not shown) spaced from each other about the periphery of the tubular member. As illustrated, each crossed circle represents the same tube in the tubular member 3a. Similarly, the next two adjacent tubular members 3b, 30 each comprise three helically coiled parallel tubes; however, the axial distance between each coil is greater than the corresponding distance in the inner tubular member. The tubes of each also being disposed on the same pitch angle.

While the tubular members 3a, 3b, 30 form a first group, a second group is formed by the next three tubular members 3d, 3e, 3 The tubular members in this second group are built up from four helically coiled parallel tubes. As illustrated, each crossed circle of each of these tubular members indicates the same tube in the tubular members. The axial distances between the coils of the tubular members 3e and 3) are also greater than that in the tubular member 3d.

The next group is formed by three tubular members 3g, 3h, 3i each of which is formed by fiive parallel tubes, the axial distances between the coils of the tube members 311 and 3i being greater than that in the tube member 3g. The further groups of tubular members are built up in a corresponding manner.

It has been found that although the groups are formed in the above manner that the temperature of a working medium flowing through the tubes is very uniform in the tubular members and that the temperature of the medium flowing around the tubes with respect to a plane perpendicular to the axis of the tubular members is also very uniform.

In order to support the individual tube coils of the tubular members within the space between the displacement member 1 and casing 2, four axially extending comb-like carrying rods 4 are distributed over the periphery of each tubular member. Each carrying rod 4 has outstanding prongs 5 which are each bent at the end to engage around a portion of a tube periphery. The carrying rods 4 for the innermost tubular member 3a are attached to the displacement member 1, as by tack weld- 3 ing, while the remaining carrying rods 4 are selectively secured to either or both of four radial arms 6,7 'ad jacent to both the top and bottom of the displacement member 1 in spaced relation to the packet 3 of tubes. For example, the carrying rod of tubular member 3b is connected at its top end to the upper carrying arm 6 while the carrying rod of the next tubular member 30 is connected at its bottom end to the lower carrying arm 7 and the remaining carrying rods are alternately connected to the upper and lower carrying arms 6, 7. In addition, the carrying rods at the next adjacent pair of circumferentially spaced carrying arms 6, 7 are secured in a reversed manner.

In order to conduct a working medium, the helically coiled tubes of the tubular members are each connected at each of their respective ends to a collector (not shown) disposed within the casing 2.

In order to construct the heat exchanger the tubular members are first made in the form of tubular cylinders by the helical bending of the required number. Next, four of the carrying rods 4 with the prongs 5 still straight are then inserted'into each tubular cylinder from the inside. The tubular cylinders thus prepared are then pushed over a template of adjustable diameter and imparted with the slightly conical shape to be assumed in the completed heat exchanger. Thereafter, the prongs 5 of the carrying rods 4 are bent to engage with the peripheries of the tubes. The slightly conical tubular members thereby form rigid transportable structures which are next positioned around the displacement member 1 in sequential order outwardly of the displacement member 1. The tubular members are inserted flush within one another during this positioning step. Subsequently, the carrying arms 6, 7 are secured, as by welding, adjacent to the top and bottom ends of displacement member 1. Finally, the top and bottom ends of the carrying rods 4 are twisted and secured, as by welding, to the carrying arms 6, 7. The casing 2 can then be positioned around the packet 3 of tubes.

Alternatively, instead of twisting the ends, the carrying rods can be connected to the carrying arms without twisting.

Referring to FIG. 2, the tubes 21 of each tubular member can also be coiled alternately in opposite directions.

The invention thus provides a heat exchanger wherein the slightly conical shape of the individual tubular members enables the packet of tubes to be readily assembled. Moreover, a tubular member can be repaired without any change in shape in the remaining tubular members. For example, in order to repair a tubular member, the connections between the carrying rods and carrying arms are first released; next, the tubular members alongside the defective tubular member are removed and thereafter, the defective tubular member is pulled. After, the defective tubular member is repaired or replaced, the packet of tubes is reassembled by insertion of the removed tubular members into one another.

Additionally, since the displacement member 1 and the upper carrying arms 6 can be made hollow, such can be used as inlets and distributors for the medium flowing through the tubes.

What is claimed is:

1. A heat exchanger comprising a displacement member;

a casing enclosing said displacement member in spaced relation thereto to define an annular space therebetween; and

a plurality of tubular members disposed in the annular space between said displacement member and said casing, each of said tubular members being of a different diameter from the others of said tubular members and of a slightly conical shape, and each of said tubular members including a plurality of helically coiled tubes of equal length.

2. A heat exchanger as set forth in claim 1 wherein said displacement member and said casing have a slightly conical shape corresponding to the conical shape of said tubular members.

3. A heat exchanger as set forth in claim 1 wherein said tubes of each tubular member are coiled alternately in opposite directions.

4. A heat exchanger as set forth in claim 1 which further comprises means for supporting said tubular members between said displacement member and said casing, said means including a plurality of carrying rods, each said carrying rod being disposed adjacent one of said tubular members in axial relation therewith and being secured to said coiled tubes therein.

5. A heat exchanger as set forth in claim 4 wherein each said carrying rod is of a comb shape having outstanding prongs engaged around a peripheral portion of each of said coiled tubes of a respective tubular member.

6. A heat exchanger as set forth in claim 4 wherein said means further includes a plurality of radial arms secured to said displacement member above and below said tubular members, said carrying rods being secured to said carrying arms.

7. A heat exchanger as set forth in claim 6 wherein said carrying rods are alternately secured to said carrying arms above and below said tubular members.

8. A heat exchanger as set forth in claim 6 wherein said displacement member is hollow and said carrying arms above said tubular members are hollow, said displacement member and said hollow carrying arms being in communi cation with each other and with said coiled tubes to provide an inlet and distributor for said coiled tubes of said tubular members.

9. A heat exchanger as set forth in claim 1 wherein said tubular members have a conicity of from 0.3 to 5.0%.

References Cited UNITED STATES PATENTS 2,508,247 5/1950 Giauque l63 3,116,790 1/1964 Walter 165-l63 3,212,571 10/1965 Romanos 165-163 3,256,932 6/ 1966 Schlichting l65163 FOREIGN PATENTS 685,283 4/ 1964 Canada.

ROBERT A. OLEARY, Primary Examiner A. W. DAVIS, Assistant Examiner US. Cl. X.R.

PO-lObO UNITED S'I'A'I'I'IS PATENT (JFFICE'I CERHFICATE OF CORRECFEQN Patent No. 3,509,939 Dated y 5, 1970 Inventor-(s) Max M51297,

It; is certified that error appears in the above-identified patent and that; said Letters Patent are hereby corrected as shown below:

Column 1, line 18, after "tubu" insert lar members within the casing from carrying arms-- Column 2, line 52, "fiive" should be --five-- (SEAL) Atbest:

EdwardM. Fletdm'Jr.

Austins mm: 1:: mum. at.

Gomiaaionar of Patents 

